Sewing machine with a needle positioning device

ABSTRACT

A sewing machine so designed as to cause an arm shaft to be subject to different drive controls according to the operating position of a selection knob, though a controller may be continuously depressed in the same manner, wherein, under the first operating position of the knob, the depression of the controller effects continuous normal stitching and the release of the controller brings the arm shaft to rest at a predetermined angular position; under the second operating position of the knob, the depression of the controller causes the arm shaft to make one rotation and be brought to rest at a predetermined angular position regardless of the succession of the depression of the controller; and under the third operating position of the knob, the bobbin winder is actuated with the arm shaft kept inoperative at a predetermined angular position independently of the depression of the controller.

United States Patent [191 Sasaki Dec. 25, 1973 [54] SEWING MACHINE WITHA NEEDLE 2,376,648 5/1945 Anderson 1 12/219 R POSITIONING DEVICE3,479,976 11/1969 Flach et a1. 1 12/219 R [75] inventor: Toshio Sasaki,lnazawa-chi, Japan [73] Assignee: Brother Kogyo Kabushiki Kaisha,

Mizuho-ku, Nagoya-shi, Japan [22] Filed: Dec. 27, 1971 [21] Appl. No.:212,327

[30] Foreign Application Priority Data Dec. 30, 1970 Japan 45/125473Dec. 31, 1970 Japan 45/128236 [52} US. Cl 112/219 A [51 Int. Cl D05b69/22 [58] Field of Search 112/219 R, 219 A,

[56] References Cited UNITED STATES PATENTS 3,404,767 10/1968 Farnum112/219 A 3,358,628 12/1967 Kosrow et al.... 112/219 A 2,942,564 6/1960Larys et a1. 112/219 A 3,388,681 6/1968 Fujita 112/220 3,460,772 8/1969Bono 112/218 A Primary Examiner-H. Hampton Hunter Att0rney-Robert D.Flynn et a1.

[ 5 7 ABSTRACT A sewing machine so designed as to cause an arm shaft tobe subject to different drive controls according to the operatingposition of a selection knob, though a controller may be continuouslydepressed in the same manner, wherein, under the first operatingposition of the knob, the depression of the controller effectscontinuous normal stitching and the release of the controller bringsthe'arm shaft to rest at a predetermined angular position; under thesecond operating position of the knob, the depression of the controllercauses the arm shaft to make one rotation and be brought to rest at apredetermined angular position regardless of the succession of thedepression of the controller; and under the third operating position ofthe knob, the bobbin winder is actuated with the arm shaft keptinoperative at a predetermined angular position independently of thedepression of the controller.

19 Claims, 23 Drawing Figures PATENTED 3.780.681

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SEWING MACHINE WITH A NEEDLE POSITIONING DEVICE This invention relatesto a sewing machine capable of resting the arm shaft at a predeterminedangular position thereof and more particularly to a household sewingmachine. It is a well-known process to automatically bring, uponcompletion of sewing, the arm shaft to rest at a predetermined angularposition, for example, with the needle positioned above a work fabric. Adevice for carrying out said process is generally referred to as aneedle positioning device.

With a household sewing machine, however, this device has not yet beenmade commercially available, except for a few cases. This may be due to,among other things, excessive cost, complicated operation andinsufficient structural durability. Particularly, the fact that the costof providing said needle positioning device is too high for the valuederived from its use poses the most difficult problem to resolve.

Referring now to a commercially available household sewing machinedhaving the aforementioned process practically adopted, the motor is sodesigned as to be brought to rest at a point corresponding to thepredetermined angular position at which the arm shaft stops.Accordingly, said needle positioning device comprises a first electriccircuit for driving the motor at a speed according to the manner inwhich the controller is depressed; a second electric circuit foroperating the motor at a fixed low speed when the controller is releasedfrom depression; and switch means for deenergizing the second electriccircuit when the arm shaft is brought to rest at a predetermined angularposition. From the viewpoint of utility value, however, said needlepositioning device is still too expensive to be deemed fully successfulin terms of cost.

A mechanism for basting with broad stitch intervals is already disclosedin US. Pat. Nos. 3,433,189, 3,515,082 and 3,598,071. However, there hasnot yet been proposed a basting mechanism built in the needlepositioning device, that is, a type wherein, under normal condition, thearm shaft is continuously driven while the controller is depressed, andbrought to rest at a predetermined angular position when the controlleris released from depression, but in case of basting, operation of singlemanual control means causes the arm shaft to make one rotation upondepression of the controller so as to be brought to rest at apredetermined angular position, even though said depression may becontinued in the same manner, thereby enabling a single stitch to beformed.

This invention relates to a sewing machine and more particularly to aneedle poitioning device for a household sewing machine, said devicebeing so designed as to cause the arm shaft of the machine to be subjectto different drive controls according to the operating position of aselection knob, though a controller may be continuously depressed in thesame manner.

The sewing machine of this invention has a device for controlling thedrive of the arm shaft in many ways, whereby, when the controller isdepressed with the selection knob set at the first operating position,the arm shaft of the sewing machine is driven at a speed correspondingto the manner in which the controller is depressed, so as to performnormal stitching; upon release of the controller from depression, thearm shaft makes several rotations at a slow speed to be brought to restat a predetermined angular position; when the controller is depressedwith the selection knob set at the second operating position, the armshaft makes just one rotation to be brought to rest at a predeterminedangu lar position, regardless of the succession of the depression of thecontroller, so as to form a single stitch, thereby enabling basting tobe carried out utilizing said single stitch forming operation; and whenthe controller is depressed with the selection knob set at the thirdoperating position, the arm shaft is not driven at all, though thecontroller may be continued to be depressed, but brought to rest at apredetermined angular position, thereby permitting the bobbin windingutilizing the idle rotation around the arm shaft of the drive elementconnected to the motor.

As mentioned above, this invention provides a household sewing machinewhose arm shaft is subject to different drive controls according to theoperating position of a selection knob, though a controller may becontinuously depressed in the same manner, thus promising application ina wide field and ensuring good utility in terms of cost.

It is accordingly an object of this invention to provide a sewingmachine equipped with a novel, improved needle positioning device freefrom the drawbacks encountered with the prior art type.

Another object of the invention is to provide a sewing machined equippedwith a needle positioning device capable of controlling the drive of thearm shaft for normal stitching as well as for basting selectively bysingle manual control means.

Still another object of the invention is to provide a sewing machineequipped with a needle positioning device capable of controlling thedrive of the arm shaft for normal stitching as well as for bobbinwinding selectively by a single manual control means.

A further object of the invention is to provide a sewing machinedequipped with a needle positioning device capable of controlling thedrive of the arm shaft for normal stitching, basting and bobbin windingselectively by a single manual control means.

The present invention can be more fully understood from the followingdetailed description when taken in conjunction with the appendeddrawings, in which:

FIG. 1 is a perspective view of a sewing machine according to anembodiment of this invention;

FIG. 2 is a right side view of the sewing machine of FIG. 1, indicatingthe part arranged according to an embodiment of the invention with theflywheel and cover taken off;

FIG. 3 is a sectional view on line 3-3 of FIG. 2;

FIG. 4 is a side view of FIG. 2 as taken from the right side with aframe taken off;

FIG. 5 is a top view of FIG. 3;

FIG. 6 is a perspective view of the disassembled parts constituting themain section of the sewing machine of 'FIG. 1;

FIG. 7 is a side view, partly in section, of FIG. 5 as taken on line7-7;

FIG. 8 is a sectional view on line 88 of FIG. 7;

FIG. 9 illustrates an electric circuit used in said sewing machine;

FIG. 10 is a right side view of the sewing machine corresponding to FIG.2 illustrating the operation of the sewing machined of the invention fornormal stitchmg;

FIGS. 1 1 and 12 are right side view of the sewing machine correspondingto FIG. 2 showing the operation of the sewing machine of the inventionfor basting;

FIG. 13 is a right side view of the sewing machine corresponding to FIG.2 presenting the operation of the sewing machine of the invention forbobbin winding;

FIGS. 14, and 16 respectively indicate the disassembled partsconstituting the selection knob section set for normal stitching,basting and bobbin winding;

FIG. 17 is a sectional view corresponding to FIG. 8 showing a differentoperating condition therefrom; and

FIGS. 18 to 23 represent another embodiment of the invention: FIG. 18 isa sectional view, partly in section, corresponding to FIG. 3 showing theconstruction of clutch section and the fitting section of the flywheel;FIG. 19 is a sectional view on line 19-19 of FIG. 18; FIG. is a frontview of the flywheel; and FIGS. 21 to 23 are views corresponding toFIGS. 18 to 20 respectively showing changes in the predetermined angularposition of the arm shaft.

There will now be described by reference to the appended drawings asewing machine according to an embodiment of this invention. Referringto FIGS. 1 to 8, the sewing machine of FIG. 1 is a lock stitch type. Amachine frame 11 consists of a cylindrical bed 2 disposed on a base 1, astandard 3 erected from the base 1 and a bracket arm 4 supported by thestandard 3 so as to overhang above said cylindrical bed 2. An arm shaft12 of the sewing machine is rotatably mounted on the frame 1 1. This armshaft 12 controls the operations of all movable parts of the sewingmachine including the vertical movement of a needle bar 6 carrying aneedle 5 and a thread take-up lever 7. A collar 13 is loosely mounted onthe arm shaft 12. A rotary member 14 is secured to one end of the collar13 through a key 15. Said rotary member 14 rotates by being connected toan electric motor 92 through, for example, a V-belt 16. In that side ofthe rotary member 14 which possesses a boss section 14a, are formed aspiral groove 14b extending from the base of said boss section 14a andalso an annular groove 14c communicated with the terminal portion of thegroove 14b and disposed at a lower level than said groove 14b. In thiscase, the boss section 14a of the rotary member 14 and collor 13 may beintegrally formed. A shaftcollar 17 is disposed adjacent to the collar13 at the end of the arm shaft 12. At that part of the shaft collar 17which contacts the collar 13 is formed a flange 170. A flywheel 18 isrotatably mounted on the collar shaft 17 and the shifting of theflywheel in the axial direction is restricted by means of a stop ring18a, and the joint rotation of the arm shaft 12 and the shaft collar 17is permitted by a connection pin 19. A spriral spring 20 is wound aboutthe cylindrical portion of the collar 13. There is provided a sleeve 21so as to surround said coil spring 20. One end 20a of the spiral spring20 is drawn outward through a notch 21a formed in the sleeve 21 to beconnected to a pin 22 secured to the flange 17a of the shaft collar 17.The other end of the spiral spring 20 radially extends outward throughanother notch 21b formed in the sleeve 21 to constitute a projecting end2012. Thus is constructed in the clutch section of the sewing machine.

An auxiliary frame 23 is secured to the frame 11 by screws 24, 25 and26. At the center of the auxiliary frame 23 are erected verticallyspaced guide pins 27 and 28 which are fitted into elongate guide holes29a and 29b perforated in a switch operating lever 29, thereby enablingsaid lever 29 to be fitted to the auxiliary frame 23 in a verticallymovable state. The upper half portion of the switch operating lever 29is made flat to constitute an engagement portion 29c and the lowerportion is bent forward (to the right side of FIG. 3 or to the left sideof FIG. 4, as applicable hereinafter) to constitute a shoulder portion29d, which can be pressed against the actuator 30a of a switch 30, forexample, a microswitch fixed to the auxiliary frame 23 so as to bepositioned below the switch operating lever 29. While normally leftopen, said switch 30 is closed when its actuator 30a is depressed by theshoulder portion 29d of said lever 29. Between the shoulder portion 29dof said lever 29 and a spring holding pin 23a erected on the auxiliaryframe 23 is stretched an extension spring 31 so as to normally urge saidlever 29 to the uppermost position, thereby preventing the shoulderportion 29d of the lever 29 from depressing the actuator 30a of theswitch 30. An elongate actuating lever 32 is disposed ahead of saidswitch operating lever 29 so as to cross it. One end of said actuatinglever 32 is pivotally mounted by a pin 35 to the upper part of asupporting lever 34 the lower end of which is pivotably attached to thelower part of the auxiliary frame 23 by a stepped screw 33. At theintermediate part of said actuating lever 32 is formed an upright arm32a, the end of which is bend rearward (to the left side of FIG. 3 or tothe right side of FIG. 4, as applicable hereinafter) substantially atright angles so as to constitute a lug portion 32b. An electromagneticsolenoid 36 is attached by a screw 37 to the fitting portion 23b formedby bending a part of the auxiliary frame 23. To the end of the plunger36a of said solenoid 36 is connected the other end of the aforesaidactuating lever 32 by a connection pin 38 through an elongate hole 32cperforated in said other end so as to extend lengthwise of said lever32. Between the connection pin 38 and the spring holding pin 23c erectedon the upper part of the auxiliary frame 23 is stretched an extensionspring 39 normally to urge the plunger 36a to the uppermost position.When, as later described, there is introduced current through theelectromagnetic solenoid 36 to cause the plunger 36a to be pulleddownward against the force of the extension spring 39, then theactuating lever 32 rotates about the pin 35 clockwise of FIG. A rockablelever 40 is bent substantially at the center with said bent partpivotally mounted on the auxiliary frame 23 by a screw 41. One endportion of said rockable lever 40 is disposed between the aforesaidswitch operating lever 29 and actuating lever 32. At the tip of said oneend portion is erected a pin 42 which in turn is fitted into an elongatehole 32d perforated substantially at the center of the actuating lever32 so as to extend lengthwise thereof. Further substantially at thecenter of the switch operating lever 29 is bored a vertically elongatehole 29e, into which there is fitted a pin 43 erected substantially atthe center of one half arm of the rockable lever 40. The other half armof the rockable lever 40 is directed downward. At the lower end of saidarm is formed an engagement portion 40a so projected as to engage thelater described lock cam. An intermediate lever 44 is rotatably fittedby a pin 45 to the supporting portion 23d projectively mounted on theauxiliary frame 23. The lower part of said lever 44 extends below thelug portion 32b of the actuating lever 32. At the end of said lower partis formed a contact portion 44a extending downward slantwise forward(FIGS. 4 and 6). At the top of said intermediate lever is formed a bentportion 44b directed to the boss 14a of the rotary member 14. To saidbent portion 44b is rotatably attached by a pin 47 the substantiallymiddle part of a restraining lever 46. At the upper end of the lever 46is formed an engagement pawl 46a engageable with the spiral groove 14band annular groove 14c (FIG. 4). At the lower end of said restraininglever 46 is provided on engagement portion 46b bent forward to engagethe engagement portion 290 of the switch operating lever 29 from above,thereby maintaining contact between the shoulder portion 29d of theswitch operating lever 29 and the actuator 30a of the switch 30. Aboutthe collar of the pin 45 is wound a coil spring 48, one end of whichengages the fitting portion 23d of the auxiliary frame 23 and the otherend of which engages the intermediate lever 44, thereby rendering bothintermediate lever 44 and restraining lever 46 pivotally attachedthereto rotatable clockwise of FIG. 4. This rotation is restrictedaccording as the engagement pawl 46a of the lever 46 is fitted into thegroove 14b or 14c of the rotary member 14. About the collar of the pin47 is wound a coil spring 49, one end of which engages the intermediatelever 44 and the other end of which engages the restraining lever 46 soas to render said restraining lever 46 rotatable counterclockwise ofFIG. 2. This rotation is restricted according as the engagement pawl 46aof the restraining lever 46 is pressed against the inner side walls ofthe groove 14b or 140. A stop lever 50 is bent substantially at themiddle part with said bent point pivoted to the upper part of theauxiliary frame 23 by a screw 51 and its collar 5 la. One half arm ofsaid stop lever 50 is directed toward the rear side of the upright arm32a of the actuating lever 32. The upper edge of one end portion of saidone half arm acts as a first engagement portion 50a. At the middle pointof said edge is projectively provided a second engagement portion 50bengageable with the engagement portion 46b of the restraining lever 46.To the upper end of the upright arm 32a of the actuating lever 32 ispivoted by a pin 53 an engagement member 52. Between one end of saidengagement member 52 and the actuating lever 32 is stretched a extensionspring 54 normally to render said engagement member 52 rotatableclockwise of FIG. 2, thereby causing the engagement portion 52a of saidengagement member 52 formed by bending rearward the tip of its other endportion to engage with the first engagement portion 50a of the stoplever 50. To the end of the other arm of the stop lever 50 is formed abent engagement strip 50c (FIGS. 3 and 6) directed to the rotating locusof the projecting end 20b of the spiral spring 20. On the lower sidewall of said engagement strip 500 is erected a forward extending pin 55,to which there is pivoted an auxiliary engagement strip 56 (FIG. 6). Onthe lower right side edge of said auxiliary engagement strip 56 (FIGS. 2and 6) is provided a rearward extending stopper 56a. The upper half ofsaid strip 56 is bent substantially at right angles, with the left sideedge of said upper half bent downward to form an engagement portion 56b,and the right side edge thereof bent slantwise downward to constitute anescapement 56c. Between the auxiliary engagement strip 56 and the bentportion of the stop lever 50 is stretched an extension spring 57normally to render said auxiliary engagement strip 56 rotatablecounterclockwise of FIGS. 2 and 6, thereby causing the stopper portion56a to be pressed against the end of the other arm of the stop lever 50.About the collar 51a is wound a coil spring 58, one end of which engagesthe auxiliary frame 23 and the other end of which engages the stop lever50 to render said stop lever 50 rotatable counterclockwise of FIG. 2,thereby causing the engagement portion 56b of the auxiliary engagementstrip 56 normally to position on the rotating locus of the projectingend 20b of the spiral spring 20 so as to be engaged with said projectingend b. Accordingly, where the rotary member 14, together with the collar13, rotates counterclockwise of FIGS. 2 and 6 with the engagementportion 56b of the auxiliary engagement strip 56 kept disengaged fromthe projecting end 20b of the spiral spring 20, the spiral spring 20receives by the rotation of the collar 13 a force to cause said spring20 to be more tightly wound about the collar 13, thereby permitting thejoint rotation of the coil spring 20 and collar 13. As the result, thecollar 13 and the shaft collar 17 are connected to transmit the rotationof the rotary member 14 to the arm shaft 12. Where, under the aforesaidcondition, the engagement portion 56b of the auxiliary engagement strip56 engages with the projecting end 20b of the spiral spring 20, thensaid projecting end 20b remains immovable to subject the spiral spring20 to a force loosening its winding. Accordingly, the spiral spring 20does not rotate to disconnect the rotary member 14 from the arm shaft12, resulting in the immediate stoppage of the arm shaft 12. In thiscase, the aforementioned sleeve 21 presents the excess expansion of thespiral spring 20.

There will now be described the selection knob by reference to FIGS. 2,3 and 14. In FIG. 3, a selection knob 59 is rotatably mounted on theauxiliary frame 23 by a pin 60.

On the collar of said knob 59 are integrally formed a cam 61 for settingthe position of the actuating lever 32, a notch cam 62 and lock cam 63.As shown in FIG. 14, these cams 61 to 63 have a substantially equalmaximum radius. The locating cam 61 consists of a first cam plane 61aoccupying a relatively small area with a maximum radius, a second camplane 61b adjacent thereto occupying a relatively small area with asmaller radius than the first cam plane 61a and a third cam plane 61coccupying the remaining area with a still smaller radius. This locatingcam 61 is so disposed as to cause the aforesaid cam planes to be pressedagainst the edge of the supporting lever 34. Between the upper end ofthe supporting lever 34 and the spring holding pin 23a of the auxiliaryframe 23 is stretched an extension spring 64 to render said supportinglever 34 rotatable clockwise of FIGS. 2 and 14, thereby causing the edgeof the supporting lever 34 normally to be pressed against the aforesaidcam planes of the locating cam 61. The notch cam 62 comprises a firstcam plane 62a occupying an area falling within a range of substantially200 with a maximum radius, and a second straight cam plane 62b,occupying the remaining area adjacent to said first cam plane 62a saidfirst cam plane 62a having of first to third depressions 62c to 62cformed at a peripheral space of substantially 45. To the underside ofthe auxiliary frame 23 is fixed a fitting member 65 by screws 66. Tosaid fitting member 65 is attached a notch pin 68 normally caused todeflect upward by a compression spring 67. The engagement portion 68a atthe end of the notch pin 68 is engaged with the aforesaid depressions620 to 62e. The notch cam 62 is so positioned as to have its cam planespressed against the under edge of the later described actuating lever 70for bobbin winding, which is pivoted at the intermediate part by a pin69 to the upper part of the auxiliary frame 23. Between the fittingmember 65 and the lower end of the actuating lever 70 is stretched anextension spring 71 to render said lever 70 rotatable counterclockwiseof FIGS. 2 and 14, thereby normally pressing the under edge of saidactuating lever 70 against the cam planes of the notch cam 62. Thelockcam 63 has first to third depressions 63a to 63c formed at a peripheralspace of substantially 45, said depressions 63a to 63e being engageablewith the engagement portion 40a of the rockable lever 40.when it rotatesclockwise of FIGS. 2 and 14. The relative positions of the cams 61 to 63are defined as shown in FIGS. 2 and 14, enabling normal stitching,basting and bobbin winding to be selectively carried out by rotation ofthe selection knob 59.

A support plate 72 (FIGS. 2 and is fixed by screws 73 to the upper partof the frame 11. To said support plate 72 is rotatably fitted by a pin74 the intermediate part of a rockable lever 75 bent into substantiallyequal halves. At the end of one arm of said rockable lever 75 is formeda bearing 76, which journaled a rotary spindle 77. To the lower end ofsaid spindle 77 is fitted a drive wheel 78 and to the upper end thereofis attached a bobbin (not shown). The end of the other arm of therockable lever 75 is tapered to be engageable with a forked portion 700formed at the upper end of the actu ating lever 70. When said lever 70rotates clockwise of FIGS. 2 and 14 (upward in FIG. 5), the rockablelever 75 rotates counterclockwise of FIG. 4 to detach the drive wheel 78from the end face 14d of the rotary member 14. Conversely where thebobbin winding actuating lever 70 makes a counterclockwise rotation, therockable lever turns clockwise of FIG. 5 to press the drive wheel 78against the end face 14d of the rotary member 14.

There will now be described the parts of the flywheel 18 by reference toFIGS. 6 to 8. At the flange 17a of the shaft collar 17 is formed a notch17b. A pin 79 is fixed to the flywheel 18 so as to be disposed in saidnotch 17b. To said pin 79 is rotatably fitted one end of a first link 80curved through a peripheral angle of substantially 90. To the other endof said first link 80 is rotatably fitted by a pin 82 one end of asecond link 81 curved through a peripheral angle of substantially 90.The other end of said second link 81 is rotatably fitted by a pin 83 tothe flange 17a of the shaft collar 17. At one end of the first link 80is formed a spring holder 80a. Between said spring holder 80a and pin 22is stretched an extension spring 84 normally to render the flywheel 18rotatable clockwise of FIGS. 2 and 8, thereby engaging the pin 79 withthe inner clockwise side of the notch 17b of the shaft collar 17. Underthis condition, the first and second links 80 and 81, as shown in FIG.8, present a semicircular form with substantially the same radius as theflange 17a of the shaft collar 17.

When the arm shaft 12 of the sewing machine is brought to rest with theengagement portion 56b of the auxiliary engagement strip 56 of the stoplever 50 engaged with the projecting end b of the spiral spring 20, thenthe edge of the intermediate part of the second link 81 approaches theside edge of the projecting end of the pin 55 erected on the stop lever50. Referring to FIG. 1, numeral 85 denotes the cover of theaforementioned mechanism.

There will now be described by reference to FIG. 9 the electricalcircuit of the sewing machine of this invention. Power supply terminals86 and 87 are connected to a single phase A.C. source of, for example,100 volts through a plug 9 (FIG. 1 Between the terminals 86 and 87 isconnected a series circuit consisting of a controller switch 88interlockingly operable with the controller 8 (FIG. 1) depressed by anoperator and the electromagnetic solenoid 36. One power supply terminal86 is connected to a control bus 89 through the switch 30 and the otherpower supply terminal 87 is directly connected to a control bus 90.Though normally open, the controller switch 88 is closed when theoperator depresses the controller 8 to start the sewing machine. Betweenthe control buses 89 and 90 is connected a series circuit consisting ofa thyristor or silicon controlled rectifier (SCR) 91 of the indicatedpolarity and a motor 92, for example, a series coil A.C. rectifier typemotor including field windings 92F and armature winding 92A. This motor92 drives the rotary member 14 through, for example, the previouslymentioned V- belt 16. Further between said buses 89 and 90 is connecteda series circuit including a protective resistor 93, variable resistor94, fixed low speed setting resistor 95 and diode 96 of the indicatedpolarity. Parallel with a series circuit consisting of said resistors 94and 95 is connected a surge absorption capacitor 97 to form a speedsetting circuit 98. The movable element 94a of the variable resistor 94is connected to the gate of the thyristor 91 through a diode 99 of theindicated polarity. Between the gate and cathode of said thyristor 91 isconnected a parallel circuit consisting of a bias resistor 100 and surgeabsorption capacitor 101. Referring to FIG. 9, numeral 102 is a surgeabsorption capacitor connected between the buses 89 and 90.

There will now be described the operation of the sewing machine of thisinvention arranged as described above FIGS. 2 to 8 (excluding FIG. 6)indicate the rest position of said sewing machine. Under this condition,the stop lever 50 is urged counterclockwise of FIG. 2 by the coil spring58 to cause the engagement portion 56b of the auxiliary engagement strip56 to be pressed against the projecting end 20b of the spiral spring 20,thereby disconnecting the rotary member 14 from the arm shaft 12. Theintermediate lever 44 is urged clockwise of FIG. 4 by the coil spring48, causing the restraining lever 46 to rotate in the same directionwith the engagement pawl 46a of said lever 46 engaged with the annulargroove of the rotary member 14. The plunger 36a of the electromagneticsolenoid 36 is brought to its uppermost position by the extension spring39, causing the actuating lever 32 to be urged counterclockwise of FIG.2 to a maximum extent. The rockable lever 40 connected to said actuatinglever 32 through the pin 42 is also rotated counterclockwise of FIG. 2to a maximum extent. Under this condition, the pin 43 erected on therockable lever 40 is positioned at a substantially middle point of theelongate hole 29e of the switch operating lever 29. Of course, saidswitch operating lever 29 is lifted uppermost by the extension spring31. Where the arm shaft 12 stands at rest under the aforementionedcondition, (with the projecting end 201) of the spiral spring 20 pressedagainst the engagement portion 56b of the auxiliary engagement strip 56of the stop lever 50), then the needle bar 6 and in consequence theneedle 6 reciprocated by the arm shaft 12 are lifted uppermost due tothe relative position of the projecting end 20b and the opposite end 20aof the spiral spring 20.

There will now be described the operation of the sewing machine of thisinvention for the various applications for which it is intended.

1. Normal stitching FIGS. 2, 10 and 14 present the relative positions ofthe cams 61 to 63 when the selection knob is operated for normalstitching (which is effected by setting the mark NS shown in the frontface of the knob 59 at the marker 10 indicated on the front side of thecover 85). Under the rest position of the sewing machine shown in FIG.2, the edge of the supporting lever 34 contacts the first cam plane 61aof the locating cam 61 to cause the actuating lever 32 to make a maximummovement to the left side of FIG. 2, that is, to take the extreme leftposition where the right inner wall of the elongate hole 32d closelyapproaches the pin 42. Under this condition, the engagement portion 52aof the engagement member 52 is engaged from above with the firstengagement portion 50a of the stop lever 50 and, as illustrated in FIG.4, the lug portion 32b of the actuating lever 32 faces from above thecontact portion 44a of the intermediate lever 44. The engagement portion68a of the notch pin 68 is inserted into the first depression 62c of thenotch cam 62, thereby defining the position of the cams 61 to 63. Theactuating lever 70 is rotated clockwise of FIG. 2 to a maximum extent byhaving its underside pressed against the first cam plane 62a of thenotch cam 62, thereby preventing the drive wheel 78 from contacting theend face 14d of the rotary member 14 (FIG.

When, under the aforementioned condition, the controller is depressed toclose the controller switch 88 for the start of the sewing machine, thenthe electromagnetic solenoid 36 is energized through the controllerswitch 88 to have its plunger 36a pulled downward, thereby causing theactuating lever 32 to rotate clockwise of FIG. 2. As the result, therockable lever 40 rotates in the same direction through the pin 42 tohave its engagement portion 40a engaged with the first depression 63a ofthe lock cam 63, thereby obstructing the working of the selection knob59 during the operation of the sewing machine. Rotation of said rockablelever 40 causes its pin 43 to engage the lower inner wall of theelongate hole 2% of the switch operating lever 29 to pull it down.Accordingly, the switch operating lever 29 is brought to its lowermostposition against the force of the extension spring 31 to cause itsshoulder portion 29d to depress the actuator 30a, thereby 0105- I ingthe switch 30 (FIGS. and 14). The closing ofsaid switch introducescurrent through the speed setting circuit 98 to supply the thyristor 91with an ignition signal, thereby starting the drive of the motor 92.When the actuating lever 32 rotates clockwise of FIG. 2, the stop lever50 whose first engagement portion 50a is pressed against the engagementportion 52a of the engagement member 52 also rotates clockwise of FIG. 2against the force of the coil spring 58, thereby disengaging theprojecting end 20b of the spiral spring 20 from the engagement portion56b of the auxiliary engagement strip 56. Thus, the rotary member 14driven by the motor 92 is connected to the arm shaft 12 by the action ofthe spiral spring 20 with the resultant rotation of the latter, therebystarting the normal continuous stitching. Rotation of the actuatinglever 32 causes its lug portion 32b to depress the contact portion 440of the intermediate lever 44. Accordingly, the intermediate lever'44 andthe restraining lever 46 rotatably fitted thereto rotatecounterclockwise of FIG. 4 to disengage the engagement pawl 46a of saidrestraining lever 46 from the annular groove 140 of the rotary member14. Upon said disengagement, the restraining lever 46 is rapidly rotatedcounterclockwise of FIG. 2 by the coil spring 49, causing its engagementpawl 46a to be pressed against the side wall of the boss 14a of therotary member 14 with the resultant stop of the restraining lever 46.During the depression of the controller, the lug portion 32b of theactuating lever 32 remains engaged with the contact portion 44a of theintermediate lever 44, keeping the engagement pawl 46a of therestraining lever 46 pressed against the boss 14a of the rotary member14. Rotation of the restraining lever 46 causes its engagement portion46b to be moved upward for contact with the engagement portion 29c ofthe switch operating lever 29 and the second engagement portion 50b ofthe stop lever 50 (FIG. 10).

While normal stitching is generally conducted in the aforementionedmanner, the speed of the motor 92, or sewing may be adjusted by changingthe manner in which the controller is depressed, because the movableelement 94a of the variable resistor 94 of the speed setting circuit 98is made to move according to the force of said depression during normalstitching.

When the controller is released from depression upon completion ofsewing to bring the sewing machine to rest, then the controller switch88 is opened to shut off supply of current to the electromagneticsolenoid 36, thereby causing its plunger 36a to be lifted to itsuppermost position by the extension spring 39, and also the actuatinglever 32 to return to its original position by rotating counterclockwiseof FIG. 2. As the result, the rockable lever 40 and stop lever 50 arealso brought back to the original position by rotating in the samedirection. However, the switch operating lever 29 and stop lever cannotregain the original position, because their engagement portions 290 and50b still remain engaged with the engagement portion 46b of therestraining lever 46.

The thyristor 91 is supplied with an ignition signal determined by thelow speed setting resistor 95 of the speed setting circuit 98 to causethe motor 92 to be driven at a predetermined low speed. The arm shaft 12which is still connected to the rotary member 14 at this time makes aslow rotation. Since the return of the actuating lever 32 disengages thelug portion 32b of the actuating lever 32 from the contact portion 44aof the intermediate lever 44, the intermediate lever 44 and therestraining lever 46 to be inserted into the initial portion clockwiseof FIG. 4, thereby causing the engagement pawl 46a of the actuatinglever 46 to be inserted into the initial portion of the spiral groove14b of the rotary member 14. Upon said insertion, the engagement pawl46a of the restraining lever 46 travels through the spiral groove 14btoward the periphery of the rotary member 14 as the result of itsrotation, so that the restraining lever 46 rotates clockwise of FIG. 10.Therefore, the engagement portion 46b of the lever 46 so moves as to bedisengaged from the engagement portions 290 and 50b of the switchoperating lever 29 and stop lever 50. When the rotary member 14 makessubstantially two rotations from the time when the en-

1. A sewing machine comprising: a frame, an arm shaft rotatably mountedon the frame, an electric motor for driving the arm shaft, circuit meansincluding electrical components to provide variable drive-energy forsaid motor, a manually depressible controller for regulating the speedof said motor by controlling said electrical components, clutch meansfor drivingly connecting said motor to said arm shaft, stop meansincluding: a stop member connected to the arm shaft for rotationtherewith and having a stop portion, and a stop lever mounted on theframe to move between an operative position in engagement with the stopportion of the stop member and an inoperative position out of engagementwith said stop portion of the stop member, urging means for biassingsaid stop lever in the operative position, said clutch means beingadapted to release the driving connection between said motor and saidarm shaft upon engagement of said stop lever with the stop portion ofsaid stop member, said stop means being adapted to stop the arm shaft ata predetermined angular position thereof upon engagement of said stoplever with the stop portion of said stop member, actuating meansoperably interconnected to said stop means and operative to move thestop lever to the inoperative position against the action of said urgingmeans upon depression of said controller and to hold said stop lever inthe inoperative position during the depression of said controller, fixedlow speed drive means including said motor and effective responsive torelaxation of said controller for driving said arm shaft at a fixed lowspeed, and restraining means operative responsive to relaxation of saidcontroller for mechanically holding to said stop lever in theinoperative position during a few revolutions of the arm shaft afterrelaxation of said controller, whereby when the controller is relaxed,said arm shaft is driven at the low speed during a few revolutionsthereof while the stop lever is mechanically held in the inoperativeposition by the operation of the restraining means, subsequently saidstop lever is moved to the operative position from the inoperativeposition, and when said stop lever engages with the stop portion of thestop member, the driving connection through the clutch means is releasedand the arm shaft is stopped in the predetermined angular positionthereof.
 2. A sewing machine according to claim 1, wherein saidrestraining means comprises: a rotary member rotatably mounted aroundthe arm shaft and drivingly connected to said motor, said rotary memberhaving a spiral groove and a circular groove communicated with theterminal portion of said spiral groove, and a restraining leverpivotally mounted on the frame to engage with said groove at one end andto engage with said stop lever at the other end, said restraining leverbeing adapted to engage at one end with a begining portion of saidspiral groove in response to relaxation of the controller and tosimultaneously engage at the other end with the stop lever, whereby saidstop lever is held in the inoperative position by the restraining leveruntil the restraining lever is disengaged with the stop lever by thepivotal movement imparted to said restraining lever upon rotation ofsaid spiral groove of the rotary member.
 3. A sewing machine accordingto claim 1, wherein said stop member is adapted to alter an angularposition of the stop portion by 180* relative to the arm shaft, wherebythe predetermined angular stop position of the arm shaft is shiftable by180* .
 4. A sewing machine according to claim 1, wherein said fixed lowspeed drive means includes a fixed low speed setting resistance disposedin said circuit means, said fixed low speed setting resistance beingeffective responsive to relaxation of said controller for providing lowspeed drive energy for said motor.
 5. A sewing machine according toclaim 4, wherein said circuit means includes switch means adapted to beclosed in response to depression of said controller and to be openedlate in stopping of the arm shaft in the predetermined angular positionafter relaxation of said controller.
 6. A sewing machine comprising: aframe, an arm shaft rotatably mounted on the frame, an electric motorfor driving the arm shaft, circuit means including electrical componentsto provide variable drive energy for said motor, a manually depressiblecontroller for regulating the speed of said motor by controlling saidelectrical components, a driving element rotatably mounted around saidarm shaft and connected to said motor, a driven element secured to saidarm shaft, a clutch for drivingly connecting or disconnecting saiddriving element to said driven element, said clutch being connected tosaid driven element and having a stop portion, a stop lever mounted onthe frame to move between an operative position in engagement with thestop portion of said clutch and an inoperative position out ofengagement with said stop portion of the clutch, urging means fornormally biassing said stop lever in the operative position, said clutchbeing constructed and arranged such that when said stop lever engageswith the stop portion of the clutch the driving connection between thedriven element is released and the arm shaft is stopped in apredetermined angular position thereof, actuating means operablyconnected to said stop lever and operative to move the stop lever to theinoperative position against the action of said urging means upondepression of said controller and to hold said stop lever in theinoperative position during the depression of said controller, fixed lowspeed drive means including said motor and effective responsive torelaxation of said controller for driving said driving element at afixed low speed, and restraining means operative responsive torelaxation of said controller for mechanically holding said stop leverin the inoperative position against the action of said urging meansduring a few revolution of the arm shaft after relaxation of saidcontroller, whereby when the controller is relaxed, said arm shaft isdriven at the low speed during a few revolutions thereof while the stoplever is mechanically held in the inoperative position by the operationof the restraining means, subsequently said stop lever is moved to theoperative position from the inoperative position, and when said stoplever engages with the stop portion of the clutch, the drivingconnection through the clutch is released and the arm shaft is stoppedat the predetermined angular position.
 7. A sewing machine comprising: aframe, an arm shaft rotatably mounted on the frame, an electric motor todrive the arm shaft, circuit means including a variable resistance and afixed low speed setting resistance and providing drive energy for saidmotor, a manually depressible controller for regulating the speed ofsaid motor by controlling said variable resistance, said circuit meansbeing adapted to provide low speed drive energy for said motor throughthe fixed low speed setting resistance upon relaxation of saidcontroller, a driving element rotatably mounted around said arm shaftand connected to said motor, and having a cylindrical portion, a drivenelement secured to said arm shaft, a clutch comprising a spiral springwrapped around the cylindrical portion of said driving element fordrivingly connecting or disconnecting said driving element to saiddriven element, said spiral spring haVing one end connected to saiddriven element and the other end radially projecting, a stop leverpivotally mounted on the frame to move between an operative position inengagement with the projecting end of said spiral spring and aninoperative position out of engagement with said projecting end of thespiral spring, urging means for biassing said stop lever in theoperative position, said clutch being adapted to release the drivingconnection between the driving element and the driven element uponengagement of said stop lever with said projecting end of the spiralspring, said spiral spring being constructed and arranged such that whensaid stop lever engages with the projecting end of the spiral springsaid arm shaft is stopped at a predetermined angular position thereof,actuating means operably connected to said stop lever and operative tomove the stop lever to the inoperative position upon depression of saidcontroller and to hold said stop lever in the inoperative positionduring the depression of said controller, and restraining meansoperative responsive to relaxation of said controller for mechanicallyholding said stop lever in the inoperative position during a fewrevolutions of the arm shaft after relaxation of said controller,whereby when the controller is relaxed, said arm shaft is driven at thelow speed during a few revolutions while the stop lever is held in theinoperative position against the action of the urging means by therestraining means, subsequently said stop lever is moved to theoperative position from said inoperative position, and when said stoplever engages with the projecting end of the spiral spring, this drivingconnection through the clutch is released, and the arm shaft is stoppedat the predetermined angular position thereof.
 8. A sewing machinecomprising: a frame, an arm shaft rotatably mounted on the frame, anelectric motor for driving the arm shaft, circuit means includingelectrical components to provide variable drive energy for said motor, amanually depressible controller for regulating the speed of said motorby controlling said electrical components, clutch means for drivinglyconnecting said motor to said arm shaft, stop means including: a stopmember connected to the arm shaft for rotation therewith and having astop portion, and a stop lever mounted on the frame to move between anoperative position in engagement with the stop portions of said stopmember and an inoperative position out of engagement with said stopportion of the stop member, urging means for biassing said stop lever inthe operative position, said clutch means being adapted to release thedriving connection between said motor and said arm shaft upon engagementof said stop lever with the stop portion of said stop member, said stopmeans being adapted to stop the arm shaft at a predetermined angularposition thereof upon engagement of said lever with the stop portion ofsaid stop member, actuating means operably interconnected to said stopmeans and adapted to perform a first operation to move the stop lever tothe inoperative position against the action of said urging means upondepression of said controller and a second operation to hold the stoplever in the inoperative position during the depression of saidcontroller, fixed low speed drive means including said motor andeffective responsive to relaxation of said controller for driving saidarm shaft at a fixed low speed, restraining means operative responsiveto relaxation of said controller for mechanically holding said stoplever in the inoperative position during a few revolutions of the armshaft after relaxation of said controller, and manual contral means forcontrolling the operations of said acturting means and the operation ofsaid restraining means, said manual control means being adapted to beset selectively either in a first position to enable the operations ofsaId actuating means and said restraining means or in a second positionto enable only the first operation of the actuating means and to disablethe second operation of the actuating means and the operation of therestraining means, whereby when the controller is depressed in thesecond position of said manual control means, the stop lever is moved tothe inoperative position, and instantly said stop lever is returned tothe operative position by the action of said urging means in spite of asuccession of depressions of said controller, so that the arm shaft isstopped at a predetermined angular position thereof after one revolutionthereof.
 9. A sewing machine according to claim 8, wherein saidactuating means comprises: a supporting member movably mounted on theframe, an actuating lever pivotally mounted on said supporting memberand operably engaging with the stop lever, said actuating lever beingadapted to permit a longitudinal movement thereof upon movement of saidsupporting member, and an operating member operably connected to saidactuating lever and operative responsive to depression of saidcontroller for swinging said actuating lever and moving said stop leverto the inoperative position, said manual control means being operablyinterconnected to said actuating means and being adapted to shift apivotal point of said actuating lever by the movement of the supportingmember upon selection of the manual control means.
 10. A sewing machineaccording to claim 8, wherein said manual control means is adapted todisable the operation of said fixed low speed drive means in the secondposition of the manual control means.
 11. A sewing machine comprising: aframe, an arm shaft rotatably mounted on the frame, an electric motorfor driving the arm shaft, circuit means including electrical componentsto provide variable drive energy for said motor, a manually depressiblecontroller for regulating the speed of said motor by controlling saidelectrical components, a driving element rotatably mounted around saidarm shaft and connected to said motor, a driven element secured to saidarm shaft, a clutch for drivingly connecting or disconnecting saiddriving element to said driven element, said clutch being connected tosaid driven element and having a stop portion, a stop lever mounted onthe frame to move between an operative position in engagement with thestop portion of said clutch and an inoperative position out ofengagement with said stop portion of the clutch, urging means fornormally biassing said stop lever in the operative position, said clutchbeing constructed and arranged such that when said stop lever engageswith the stop portion of the clutch the driving connection between thedriving element and the driven element is released and the arm shaft isstopped in a predetermined angular position thereof, actuating meansoperably connected to said stop lever and adapted to perform a firstoperation to move the stop lever to the inoperative position against theaction of said urging means upon depression of said controller and asecond operation to hold the stop lever in the inoperative positionduring the depression of said controller, fixed low speed drive meansincluding said motor and effective responsive to relaxation of saidcontroller for driving said driving element at a fixed low speed,restraining means operative responsive to relaxation of said controllerfor mechanically holding said stop lever in the inoperative positionagainst the action of said urging means during a few revolutions of thearm shaft after relaxation of said controller, and manual control meansfor controlling the operations of said actuating means and saidrestraining means, said manual control means being adapted to be setselectively either in a first position to enable the operations of saidactuating means and said restraining means or in a second position toenable only the first operation of the actuating means and to disablethe second operation of the actuating means and the operation of therestraining means, whereby when the controller is depressed in thesecond position of said manual control means, the stop lever is moved tothe inoperative position, and instantly said stop lever is returned tothe operative position by the action of said urging means in spite of asuccession of depressions of said controller, so that the arm shaft isstopped at the predetermined angular positon therof after one revolutionthereof.
 12. A sewing machine comprising: a frame, an arm shaftrotatably mounted on the frame, an electric motor for driving the armshaft, circuit means including electrical components to provide variabledrive energy for said motor, a manually depressible controller forregulating the speed of said motor by controlling said electricalcomponents, clutch means for drivingly connecting said motor to said armshaft, said clutch means including a driving element rotatably mountedaround said arm shaft and connected to said motor, stop means including:a stop member connected to the arm shaft for rotation therewith andhaving a stop portion, and a stop lever mounted on the frame to movebetween an operative position in engagement with the stop portion ofsaid stop member and an inoperative position out of engagement with thestop portion of the stop member, urging means for biassing said stoplever in the operative position, said clutch means being adapted torelease the driving connection between said motor and said arm shaftupon engagement of said stop lever with the stop portion of said stopmember, said stop means being adapted to stop the arm shaft at apredetermined angular position thereof upon engagement of said stoplever with the stop portion of said stop member, actuating meansoperably interconnected to said stop means and operative to move thestop lever to the inoperative position against the action of said urgingmeans upon depression of said controller and to hold said stop lever inthe inoperative position during the depression thereof; fixed low speeddrive means including said motor and effective responsive to relaxationof said controller for driving said arm shaft at a fixed low speed,restraining means operative responsive to relaxation of said controllerfor mechanically holding said stop lever in the inoperative positionduring a few revolutions of the arm shaft after relaxation of saidcontroller, manual control means for controlling operations of both saidactuating means and saId restraining means, said manual control meansbeing adapted to be set selectively either in an operative position todisable operations of both said actuating means and said restrainingmeans or in an inoperative position to enable said both operationsthereof, and a bobbin winder mounted on the frame adjacent said drivingelement to be selectively shiftable into and out of driving contact withsaid driving element, whereby when the controller is depressed in theoperative position of said manual control means, the stop lever is notmoved to the inoperative position, the driving connection through theclutch means is not established and only the driving element is driven,while the arm shaft is stopping in the predetermined angular position,so that the bobbin winder is operated by shifting thereof into drivingcontact with said driving element.
 13. A sewing machine according toclaim 12, wherein said bobbin winder is operably connected to the manualcontrol means through a linkage and adapted to be automatically shiftedinto or out of driving contact with said driving element in response toselection of said manual control means in the operative position or inthe inoperative position thereof respectively.
 14. A sewing machineaccording to claim 12, wherein said manual control means is adapted todisable the operation of saiD fixed low speed drive means in theoperative position of manual control means.
 15. A sewing machinecomprising: a frame, an armshaft rotatably mounted on the frame, anelectric motor for driving the arm shaft, circuit means includingelectrical components to provide variable drive energy for said motor, amanually depressible controller for regulating the speed of said motorby controlling said electrical components, a driving element rotatablymounted around said arm shaft and connected to said motor, a drivenelement secured to said arm shaft, a clutch for drivingly connecting ordisconnecting said driving element to said driven element, said clutchbeing connected to said driven element and having a stop portion, a stoplever mounted on the frame to move between an operative position inengagement with the stop portion of said clutch and an inoperativeposition out of engagement with said stop portion of the clutch, urgingmeans for normally biassing said stop lever in the operative position,said clutch being constructed and arranged such that when said stoplever engages with the stop portion of the cluch the driving connectionbetween the driving element and the driven element is released and thearm shaft is stopped at a predetermined angular position thereof,actuating means operably connected to said stop lever and operative tomove the stop lever to the inoperative position against the action ofsaid urging means upon depression of said controller and to hold saidstop lever in the inoperative position during the depression of saidcontroller, fixed low speed drive means including said motor andeffective responsive to relaxation of said controller for driving saiddriving element at a fixed low speed, restraining means operativeresponsive to relaxation of said controller for mechanically holdingsaid stop lever in the inoperative position against the action of saidurging means during a few revolutions of the arm shaft after relaxationof said controller, manual control means for controlling the operationsof both said actuating means and said restraining means, said manualcontrol means being adapted to be set selectively either in an operativeposition to disable operations both said actuating means and saidrestraining means or in an inoperative position to enable said bothoperations thereof, and a bobbin winder mounted on the frame adjacentsaid driving element to be selectively shiftable into and out of drivingcontact with said driving element, whereby when the controller isdepressed in the operative position of said manual control means, thestop lever is not moved to the inoperative position, the drivingconnection through the clutch is not established and only the drivingelement is driven, while the arm shaft is stopping in the predeterminedangular position, so that the bobbin winder is operated by shiftingthereof into driving contact with said driving element.
 16. A sewingmachine according to claim 15, further comprising: a bobbin windermounted on the frame, and third means for operating the bobbin winderfor stopping the arm shaft at the predetermined angular position thereofby depression of the controller.
 17. A sewing machine comprising: aframe, an arm shaft rotatably mounted on the frame, an electric motorfor driving the arm shaft, circuit means including electrical componentsto provide variable drive energy for said motor, a manually depressiblecontroller for regulating the speed of said motor by controlling saidelectrical components, a driving element rotatably mounted around saidarm shaft and connected to said motor, a driven element secured to saidarm shaft, a clutch for drivingly connecting or disconnecting saiddriving element to said driven element, a bobbin winder mounted on theframe adjacent said driving element to be selectively shiftable into andout of driving conTact with the driving element, said clutch beingconnected to said driven element and having a stop portion, a stop levermounted on the frame to move between an operative position in engagementwith the stop portion of said clutch and an inoperative position out ofengagement with said stop portion of the clutch, urging means fornormally biassing said stop lever in the operative position, said clutchbeing constructed and arranged such that when said stop lever engageswith the stop portion of the clutch the driving connection between thedriving element and the driven element is released and the arm shaft isstopped at a predetermined angular position thereof, actuating meansoperably connected to said stop lever and adapted to perform a firstoperation to move the stop lever to the inoperative position against theaction of said urging means upon depression of said controller and asecond operation to hold the stop lever in the inoperative positionduring the depression of said controller, fixed low speed drive meansincluding said motor and effective responsive to relaxation of saidcontroller for driving said driving element at a fixed low speed,restraining means operative responsive to relaxation of said controllerfor mechanically holding said stop lever in the inoperative positionagainst the action of said urging means during a few revolutions of thearm shaft after relaxation of said controller, and manual control meansfor controlling the operations of said actuating means and saidrestraining means, said manual control means being adapted to be setselectively in three different positions, the first position to enablethe operations of the actuating means and the restraining means, thesecond position to enable only the first operation of the actuatingmeans and to disable the second operation of the actuating means and theoperation of the restraining means, and the third position to disablesaid all operations thereof, whereby in the first position of saidmanual control means the arm shaft is continuously driven during thedepression of said controller and is stopped at the predeterminedangular position thereof after relaxation of said controller, in thesecond position of said manual control means the arm shaft is stopped atthe predetermined angular position thereof after one revolution of thearm shaft in spite of a succession of the depressions of saidcontroller, and in the third position of said manual control means thearm shaft is not driven in spite of the depression of said controllerand only the driving element is driven at that time.
 18. A sewingmachine comprising: a frame, an arm shaft rotatably mounted on theframe, an electric motor for driving the arm shaft, circuit meansincluding variable speed-setting components, a manually depressiblecontroller for regulating the speed of said motor by controlling saidspeed-setting components, and a needle positioning device for stoppingthe arm shaft at a predetermined angular position thereof, said needlepositioning device comprising: first means operative responsive torelaxation of said controller to stop the arm shaft at the predeterminedangular position thereof after relaxation of the controller, secondmeans operative in response to depression of said controller to stop thearm shaft at the predetermined angular position thereof after onerevolution of the arm shaft even when the controller is depressed, andmanual control means operated by a selection knob operative outside theframe prior to depression of said controller, said manual control meansbeing adapted to be set selectively either in a first position to effectthe operation of said first means or in a second position to effect theoperation of said second means, whereby said arm shaft is subject todifferent drive control according to the selected position of the manualcontrol means even though the controllEr may be continuously depressedin the same manner.
 19. A sewing machine according to claim 18 furthercomprising a bobbin winder mounted on the frame, and wherein said needlepositioning device further comprises third means operative to actuatethe bobbin winder with its shaft stopped at its predetermined angularposition by depression of the controller, said manual control meansbeing further adapted to be set selectively in a third position toeffect the operation of the third means by the selection knob.